This resource program is designed to provide a central resource to support a broad multidisciplinary investigation of squirrel monkeys (Saimiri sciureus) in health and disease, and to provide monkeys, monkey care and consultation for users of this resource representing the Departments of Comparative Medicine, Anatomy, Pathology, and Pharmacology. Special emphasis will be placed on pathologic anatomy of squirrel monkey diseases, continuation of the resource collaboration projects, and particularly on the further characterization of squirrel monkeys as models for studies on cholelithiasis and lactose intolerance.